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Web Coverage Service (WCS)

Purpose

On this page information about and discussion of the Web Coverage Service (WCS) standards suite is provided. The standards are available from http://www.opengeospatial.org/standards/wcs.

Working Group chair is Steven Keens, co-chair is Peter Baumann. For the moment being, Peter Baumann is leading the group; he is also editor of the WCS 2.0 specification set.

News

The WCS 2.0 suite has been drafted, successfully passed the public RFC (Request For Comment) period, and is now being voted by the OGC TC until June 20, 2010.

The WCS 2.0 draft has several significant advantages over previous versions: it relies on the GML coverage model, leading to increased interoperability across OGC standards; main features are:

  • extends beyond pure raster grids to support all coverage types which GML 3.2.1 knows, e.g., irregular grids;
  • crisp and modular, consisting of a small mandatory core and a structured universe of optional extensions;
  • harmonized with OGC OWS-Common, GML, SWE, WMS, WCPS, and WPS
  • has a clear, formally specified syntax (XML Schema) and semantics (Schematron) easing understanding and implementation;
  • testable: for the first time, pixel contents is subject to conformance testing.

Background

"The Web Coverage Service (WCS) supports electronic retrieval of geospatial data as "coverages" – that is, digital geospatial information representing space-varying phenomena.

A WCS provides access to potentially detailed and rich sets of geospatial information, in forms that are useful for client-side rendering, multi-valued coverages, and input into scientific models and other clients. The WCS may be compared to the OGC Web Map Service (WMS) and the Web Feature Service (WFS); like them it allows clients to choose portions of a server's information holdings based on spatial constraints and other criteria.

Unlike the WMS [OGC 06-042], which portrays spatial data to return static maps (rendered as pictures by the server), the Web Coverage Service provide s available data together with their detailed descriptions; defines a rich syntax for requests against these data; and returns data with its original semantics (instead of pictures) which may be interpreted, extrapolated, etc. – and not just portrayed.

Unlike WFS [OGC 04-094], which returns discrete geospatial features, the Web Coverage Service returns coverages representing space-varying phenomena that relate a spatio-temporal domain to a (possibly multidimensional) range of properties."

-- WCS 1.1.2 [OGC 07-067r3]

WCS Overview and Links

This page hosts non-normative material about WCS.
The WCS suite consists of the following documents:

  • WCS (current document version: 07-067r5)
  • extensions:
    • WCS-T, the WCS Transaction Extension (current document version: 07-068r4)
    • WCPS, the WCS Processing Extension (current document version: 08-068r2 and 08-059r3); see also the OGC Network info on WCPS

Official releases of WCS specifications are available here:

Groups engaged in WCS

OGC working groups directly concerned with coverages

  • Web Coverage Service (WCS) Standards Working Group (WCS.SWG) -- purpose: maintenance and further development of the WCS implementation specification (Working Group chairs: Steven Keens, Peter Baumann)
  • Web Coverage Processing Service (WCPS) Group -- purpose: development of the WCPS implementation specification (Working Group chair: Peter Baumann)
  • Coverages Working Group -- purpose: general discussion about coverage-related topics (Working Group chairs: Peter Baumann, Charles Roswell)

Best practice & application reports:

  • UCL's ICEDS service includes a Guidelines document on the installation, data preparation, and set-up needed to serve global datasets such as SRTM at full resolution by WCS as well as WMS. The document focuses on the use of FOSS tools such as the Minnesota Map Server.

The following OGC specifications make use of coverages:

  • Sensor Web Enablement (SWE)
  • (to be completed)

Further groups:

WCS Implementations & Installations

 

We classify offerings into "client" (software), "server" (software), and "service".Note that the list below is not authoritative (the page maintainers
do not regularly check the links) and does not constitute any
endorsement nor a statement of OGC nor anybody else about conformance.
Information is provided as is.

Disclaimer

This website contains statements by both members of the WCS Standards Working Group (WCS.SWG) and other groups and individuals. Any opinions expressed by members of the WCS.SWG are reflecting their individual position. Under no circumstance any information provided here can be interpreted as normative or as a statement on directions any OGC specification (in particular: the WCS suite) is taking, is likely to be taken, or is intended to be taken. Further, no information provided here can be interpreted as endorsed by OGC. Finally, links from this page to web space outside the domain of the OGC do not constitute any endorsement or support for the contents of the web page / site referenced; generally speaking, OGC is not responsible in any way for the contents of such sites.